The present invention relates to a dual pipe rod assembly section with a probe arranged in the dual pipe rod assembly section, a horizontal drilling device and a probe housing.
The following discussion of related art is provided to assist the reader in understanding the advantages of the invention, and is not to be construed as an admission that this related art is prior art to this invention.
The invention relates to a dual pipe rod assembly section including an inner rod section and an outer rod section, having a probe arranged in the dual pipe rod assembly section a horizontal drilling device and a probe housing.
In rod assembly based drilling in the ground in particular for the purpose of generating so called horizontal bore holes which extend substantially parallel or at a relatively small inclination angle relative to the ground surface, a drill head is driven by means of a rod assembly by a drive device which is arranged above ground or in an excavation pit. The rod assemblies used in this case are made of individual pipe rod sections which are connected to one another, and which—corresponding to the drilling course—are placed at the rear end of the already drilled rod and connected to the latter.
For rock drilling, i.e. a drilling in rock or rocky earth formations substantially two different designs of rock drilling devices are established in the market place which function without a fast rotation of the rod assembly which is in contact with the wall of the bore hole.
A first one of these designs is based on the use of an in-hole motor, which drives the drill head directly and not via the drill rod assembly. Rather, the unit of drill head and in hole motor is fixed to the front side of the drill rod assembly via which the required axial pressure for driving the bore hole forward is applied. As in-hole motors so called mud motors are commonly used in which a drive fluid is conducted though a turbine under high pressure to cause the rotation.
The second common design for rock drilling devices is based on the use of a dual rod assembly which in the following is also referred to as dual pipe rod assembly. In these machineries, the drill head is additionally rotatingly driven via an inner rod assembly of the dual pipe rod assembly by a driving device which is arranged above ground or in an excavation pit, and which also ensures the forward drive of the motor. The inner rod assembly is rotatably supported in an outer rod assembly of the dual pipe rod assembly.
In the known rock drilling devices with dual pipe rod assembly the individual rod sections of the outer rod assembly as well as the inner rod assembly are either bolted to one another or inserted into one another.
For controlling the position and the directional accuracy during drilling, it is possible to install a (measuring) probe in a housing in or on the drill head, which during drilling allows a maximally accurate position determination from above ground. The determination of the position of the drill head is usually achieved by a measuring probe which emits an electromagnetic wave. Beside the determination of the inclination angle and the rolling of the probe as well as the extension “right/left” by a receiver carried along by a user above ground (“Walk-Over-Method”) further data can be emitted by the probe via the electromagnetic wave.
The probes or respectively, sensors require a supply voltage, which can be supplied via accumulators which are arranged on the drill head or a cable line to an external voltage source—as it is described for example in U.S. Pat. No. 5,833,015 A. The runtime of accumulators is limited which can lead to problems when using accumulators. The use of cables on the other hand poses the risk that because of strong mechanical stress, the cable can be damaged. When using a probe which is connected to a cable in a dual pipe rod assembly, it is known to guide the cable in the internal space between the inner rod assembly and the outer rod assembly, wherein the probe is fastened to the outer housing in the annulus.
It would therefore be desirable and advantageous to provide an improved dual pipe rod assembly section with a probe arranged in the dual pipe rod assembly section, an improved horizontal drill device with such a dual pipe rod assembly section and in particular a probe housing for a dual pipe rod assembly, in which the service time is increased and a simple mounting is nevertheless possible.